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Full-Text Articles in Quantum Physics

Experimental Characterization Of Coherent Magnetization Transport In A One-Dimensional Spin System, Chandrasekhar Ramanathan, Paola Cappellaro, Lorenza Viola, David G. Cory Oct 2011

Experimental Characterization Of Coherent Magnetization Transport In A One-Dimensional Spin System, Chandrasekhar Ramanathan, Paola Cappellaro, Lorenza Viola, David G. Cory

Dartmouth Scholarship

We experimentally characterize the non-equilibrium, room-temperature magnetization dynamics of a spin chain evolving under an effective double-quantum (DQ) Hamiltonian. We show that the Liouville space operators corresponding to the magnetization and the two-spin correlations evolve 90 degrees out of phase with each other, and drive the transport dynamics. For a nearest-neighbor-coupled N-spin chain, the dynamics are found to be restricted to a Liouville operator space whose dimension scales only as N2, leading to a slow growth of multi-spin correlations. Even though long-range couplings are present in the real system, we find excellent agreement between the analytical predictions …


The Quantum Dialectic, Logan Kelley May 2011

The Quantum Dialectic, Logan Kelley

Pitzer Senior Theses

A philosophic account of quantum physics. The thesis is divided into two parts. Part I is dedicated to laying the groundwork of quantum physics, and explaining some of the primary difficulties. Subjects of interest will include the principle of locality, the quantum uncertainty principle, and Einstein's criterion for reality. Quantum dilemmas discussed include the double-slit experiment, observations of spin and polarization, EPR, and Bell's theorem. The first part will argue that mathematical-physical descriptions of the world fall short of explaining the experimental observations of quantum phenomenon. The problem, as will be argued, is framework of the physical descriptive schema. Part …


Dynamical Critical Scaling And Effective Thermalization In Quantum Quenches: Role Of The Initial State, Shusa Deng, Gerardo Ortiz, Lorenza Viola Mar 2011

Dynamical Critical Scaling And Effective Thermalization In Quantum Quenches: Role Of The Initial State, Shusa Deng, Gerardo Ortiz, Lorenza Viola

Dartmouth Scholarship

We explore the robustness of universal dynamical scaling behavior in a quantum system near criticality with respect to initialization in a large class of states with finite energy. By focusing on a homogeneous XY quantum spin chain in a transverse field, we characterize the nonequilibrium response under adiabatic and sudden quench processes originating from a pure as well as a mixed excited initial state, and involving either a regular quantum critical or a multicritical point. We find that the critical exponents of the ground-state quantum phase transition can be encoded in the dynamical scaling exponents despite the finite energy of …


Hamiltonian Dynamics In The Theory Of Abstraction, Subhajit Kumar Ganguly Jan 2011

Hamiltonian Dynamics In The Theory Of Abstraction, Subhajit Kumar Ganguly

Subhajit Kumar Ganguly

This paper deals with fluid flow dynamics which may be Hamiltonian in nature and yet chaotic.Here we deal with sympletic invariance, canonical transformations and stability of such Hamiltonian flows. As a collection of points move along, it carries along and distorts its own neighbourhood. This in turn affects the stability of such flows.